21402546 has 32 divisors (see below), whose sum is σ = 47271168. Its totient is φ = 6405840.

The previous prime is 21402527. The next prime is 21402587. The reversal of 21402546 is 64520412.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3525 + ... + 7431.

It is an arithmetic number, because the mean of its divisors is an integer number (1477224).

Almost surely, 2^21402546 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21402546, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23635584).

21402546 is an abundant number, since it is smaller than the sum of its proper divisors (25868622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21402546 is a wasteful number, since it uses less digits than its factorization.

21402546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4006.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21402546 is about 4626.2885772507. The cubic root of 21402546 is about 277.6441196033.

Adding to 21402546 its reverse (64520412), we get a palindrome (85922958).

The spelling of 21402546 in words is "twenty-one million, four hundred two thousand, five hundred forty-six".